--- a/tests/test-command-template.t	Sun Feb 14 12:42:25 2016 +0900
+++ b/tests/test-command-template.t	Sun Feb 14 12:48:14 2016 +0900
@@ -3148,6 +3148,9 @@
   text.1:be wrapped
   text.1:desc to be
   text.1:wrapped (no-eol)
+  $ hg log -l1 -T '{fill(desc, date, "", "")}\n'
+  hg: parse error: fill expects an integer width
+  [255]
 
   $ hg log -l 1 --template '{sub(r"[0-9]", "-", author)}'
   {node|short} (no-eol)